Chitosan‐Modified Hydrogel Microsphere Encapsulating Zinc‐Doped Bioactive Glasses for Spinal Cord Injury Repair by Suppressing Inflammation and Promoting Angiogenesis

Spinal cord injury (SCI) is a common nerve injury caused by external force, resulting in sensory and motor impairments. Previous studies demonstrated that inhibiting the neuroinflammation promoted SCI repair. However, these approaches are low efficient, and lack targeting specificity, and even require repeated and high doses of systemic administration. To address such issues, in the present study, chitosan-modified hydrogel microspheres encapsulating with zinc-doped bioactive glasses (CS-MG@Zn/BGs) is constructed for targeted repair of SCI. In vitro, the CS-MG@Zn/BGs effectively inhibited the acute inflammatory response initiated by microglia and promoted angiogenic activities. In vivo, CS-MG@Zn/BGs targeted the injured site, and attenuated neuroinflammation by inhibiting microglia infiltration and modulating microglia polarization toward M2 type. Furthermore, it facilitated vascular reconstruction, neuronal differentiation, axonal regeneration and remyelination at the injured site, and thereby promoted motor function recovery of SCI mice. The in vitro and in vivo results implied that CS-MG@Zn/BGs may be a promising alternative for the rehabilitation of SCI.